Percussion system



Marh 18, 196.9 J. s. sou'rHARn PERCUSSION SYSTEM Sheet of 5 Filed Oct.20, 1965 /nvenfnr JAMES S SOUTHA RD BY @wrm ATTYS.

March 18, 1969 J. s. souTHARD PERCUSSION SYSTEM Sheet Filed OCT.. 20,1965 United States Patent O Claims ABSTRACT OF THE DISCLOSURE Percussionsystem for electric organ having generators for producing sounds ofdrums, blocks and other percussion instruments and noise source forproducing signals keyed to provide brush and cymbal sounds. Thegenerators and keyers are actuated by multivibrators controlled byaccompaniment and pedal keyboards. Repeat action `and production ofalternate tones can be selectively provided'.

This invention relates generally to percussion units for electricorgans, and more particularly to a system actuated by the keys of akeyboard and/or a pedal board of an organ and which selectively producesthe sounds of a plurality of different percussion instruments.

Pipe organs as used in theaters and in other places have includedprovisions for making sounds of percussion instruments, such as drums,blocks, castinets, brush and cymbal. Electric organs have been providedhaving characteristics similar to that of theater organs, and it isdesired to provide the percussion sounds by simple and inexpensivecircuits. It is further desired that the sounds be the same or verysimilar to the sounds produced by the percussion instruments themselves.This requires that the sounds for the different percussion instrumentshave quite different characteristics. It is also desired that the systembe arranged so that the organist can use the sounds as desired withoutdeveloping new and difficult techniques.

An object of this invention is to provide an improved percussion systemfor use with an electric organ, and which is actuated by the keys of theorgan and provides the sounds of various different percussioninstruments.

A further object of the invention is to provide an electric percussionsystem which can be actuated selectively by the accompaniment manual andby the pedal board of an organ to provide one or more of a plurality ofdifferent percussion instrument sounds.

Still another object of the invention is to provide a percussion systemfor an electric organ which is actuated by the pedal board and whichprovides percussive sounds when a pedal is operated and/ or when a pedalis released.

A still further object of the invention is to provide an improvedpercussion system wherein percussive sounds can be repeated and/oralternately sounded.

A feature of the invention is the .provision of a percussion systemhaving a plurality of tone generators ywhich produce bursts of tone inresponse to pulses applied thereto, and having multivibratorsselectively operated by keys of a manual of the organ and/or a pedalboard for providing the actuating pulses.

Another feature of the invention is the provision of a percussivegenerating system including a noise generator and keyer for providing aburst of signals from the noise generator. The action of the keyer canbe controlled by multivibrators actuated by keys of an organ which alsoactuate other generators for producing percussive sounds, and may befurther controlled by a shimmer generator to produce desired brushsounds.

A further feature of the invention is the provision of a percussionactuating system for operation by the accompaniment manual of an organwhich provides an actuating pulse in response to operation of a keybelow middle 3,433,880y Patented Mar. 18, 1969 ICC C and a furtheractuating pulse in response to operation of a key above middle C. Analternator can be used to apply the actuating pulses to two generatorsin turn to provide two percussive sounds alternately.

A still further feature of the invention is the provision of apercussion system including a switch device operated by keys of thepedal board of an organ and which closes a first contact when a key isoperated and a second contact when a key is released, with the contactsbeing selectively connected to produce actuating pulses to cause percussive sounds.

The invention is illustrated in the drawings wherein:

FIG. 1 illustrates in block diagram an electric organ with thepercussion system of the invention coupled thereto;

FIG. 2 is a circuit diagram of the percussion system of FIG. 1; and

FIG. 3 is a block diagram of a more complex percussion system.

In practicing the invention there is provided a percussion system for anelectric organ for producing various percussive sounds as the organ isplayed. A plurality of -generators produce the sounds of drums, blocksand other percussion instruments. A noise source produces signals whichare keyed to provide brush and cymbal sounds. The percussion sound tonegenerators and the keyer are actuated by multivibrators controlledrespectively by the lkeys of the accompaniment keyboard and the pedalboard. The multivibrator for the accompaniment keyboard is actuated bythe individual keys and may be actuated by operation of a key belowmiddle `C and again by operation of a key above middle C. A repeater maybe provided or repeatedly actuating the generators, and theaccompaniment multivibrator 4may be connected to an alternator forinitiating two tones in turn, such as the wood block and the templeblock sounds. The pedal multivibrator can be actuated from a pedal tonekeyer or from separate contacts provided on the pedals. A double throwswitching device can be used to actuate a first pedal multivibrator whena pedal is depressed and to actuate a second pedal multivibrator whenthe pedal is released, as may be desired for brush and cymbal sounds.

In FIG. l there is shown a block diagram of an organ having a percussionor rhythm section in accordance with the invention. The organillustrated includes a solo keyboard or manual 10, an accompanimentkeyboard or manual 11, and a pedal board 12. A plurality of tonegenerators 13 apply tones to a keying circuit 14 controlled by the keyson the solo keyboard 10, and to a keying circuit 15 controlled by thekeys on the accompaniment keyboard 11. The signals passed by the keyingcircuit 14 are applied to a voicing circuit 16, with string and reedtype tone signals being applied through the string preamplifier 17 andthe string post amplifier 1S to the string power amplifier 19. The flutetone signals from the voicing circuit 16 are applied through the `flutepreamplier 21 and the ute post amplifier 22 to the ute power amplifier23. Signals applied through keying circuit 15 by control of theaccompaniment keyboard 11 are applied to voicing circuit 20, and to thestring preamplifier 17 and the ute preamplifier 21 in the same manner asthe signals from the voicing circuit 16 for the signals from the solokeyboard.

A separate tone generator 25 applies tone signals to a keying circuit 26controlled by the keys or pedals on the pedal board 12. The pedal tonesignals are applied through voicing circuit 27 and pedal amplifier 28,and then through resistor 29 to the string power amplifier 19', andthrough resistor 30 to the flute power amplifier 23. The organ systemwhich has been described has been used for a period of years.

The percussion or rhythm section for the organ makes use of anadditional Contact which is provided on the keys on the accompanimentkeyboard 11. These contacts are numbered 40 for the keys below middle Cand 41 for the keys above middle C. The contacts 40 are arranged toengage a `fixed contact 42, and the contacts 41 engage a fixed contact43. The contact 42 is connected to the junction between resistor 44 andcapacitor 45, which provides a positive potential to the contact 42. Thecontact 43 is similarly connected between resistor 46 and capacitor 47which provides a positive potential thereto. The movable contacts 4t)and 41 are all connected through the single conductor 48 to theaccompaniment multivibrator 50 for actuating the same.

The accompaniment multivibrator 50 applies a pulse of fixed amplitudeand duration in response to actuation of any key of the accompanimentkeyboard. The accompaniment multivibrator 50 is connected throughseparately actuated switches 51 and 52 to the wood block generator 53and the brush-cymbal keyer 54 respectively. Each time an actuating7pulse is applied to the wood block generator 53, a decaying burst oftone having a frequency of the order of 590 cycles per second isproduced thereby. This is represented by the waveforms a to the rightof' the wood block generator 53.

A noise generator 55 provides noise having a gaussian distributionaround 20 kilocycles which is applied to the brush-cymbal keyer 54. Whenthe switch 52 is closed, a pulse from the multivibrator t) actuates thekeyer `54 to pass a decaying burst of noise as shown by the wave b tothe right of the keyer 54. The keyer 54 is connected to switch contact56 which is grounded by switch arm 57 for short sustain of thebrush-cymbal burst. When the contact 57 is ungrounded, long sustain isprovided.

The outputs of the wood block generator 53 and of the keyer 54 areapplied to amplifier `60 which has variable gain to control the level ofthe signal. The output of amplifier 60- is applied to the string postamplifier 18 of the organ audio system by resistors 61 and 62. Thissignal is also applied to the string power amplifier 19 throughresistors 61 and 63. The output of the string post amplifier 1S isapplied to the string power amplifier 19. This provides control of thelevel by the string post amplifier 18 as well as by the amplifier 60.The level of the signals is further controlled by switch 64. When thisswitch is closed, the signal at the output of amplifier 6i) is dividedby the action of resistor 61 and the series circuit including resistor65 and capacitor 66. When the switch contact 57 is in the long sustainposition and engages contact 68, capacitor 67 is connected in parallelwith resistor 65 and capacitor 66 to further divide down the signal,particularly at the higher frequencies.

The percussion system is also actuated by the pedal manual of the organ.Pedal keyer 26 is actuated when any pedal is operated. rThe keyer 26 iscoupled to `monostable multivibrator 70, which is generally similar tothe multivibrator '50. This provides a pulse of a predeterminedamplitude and duration each time a pedal key is operated. Themultivibrator 70 is connected to separately operated switches 71 and 72.Switch 71 connects the multivibrator 70 to the keyer 54 so that thiskeyer applies brush-cymbal percussive bursts as has been described inconnection with the operation of keys on the accompaniment manual.Switch 72 applies a pulse from the multivibrator 70 to the bass drumgenerator 74 which produces a burst of tone having a frequency of theorder of 66 cycles per second. A decaying burst is produced each time apulse is applied thereto as presented by the curve c at the right of thegenerator 74. The output of the bass drum generator 74 is also appliedto the amplifier 60 together with the outputs of the wood blockgenerator 53 and the brush-cymbal keyer 54.

FIG. 2 shows the circuit diagram of the percussion system of FIG. 1. Thekeys of the accompaniment manual of the organ have contacts 40 and 41individually operated by the keys as described in connection with FIG.l.

4 Operation of any one of the contacts 40 will charge the capacitor 75by connecting the same in parallel with capacitor 45 which is chargedthrough resistor 44 from the +6 volt terminal. The voltage acrosscapacitor 75 is applied to the differentiating circuit includingcapacitor 76 and resistor 77 and positive differentiated pulses will beapplied through diode 78 to the base of transistor 79 of theaccompaniment multistable multivibrator 50. Only one pulse is providedeach time a contact 40 is closed until all contacts 4t) are released.However, resistor 82 discharges capacitor 75 so that closing of acontact 41 connects the capacitor 75 in parallel with capacitor 47 whichis charged through resistor 46 from the +6 volt supply. This willprovide a new voltage pulse across capacitor 75 which is applied to thedifferentiating circuit 76, 77 to provide a pulse through diode 78 toagain trigger the multivibrator 50.

The multivibrator 50 is of known construction and includes transistors79 and 80. Transistor 79 conducts in response to the trigger pulse tocut off transistor 80 so that a voltage pulse appears at the collectorof transistor 80 which is applied through conductor 81 to the switches51 and 52 previously described.

The wood block oscillator 53 is of the phase shift type includingtransistor having a three mesh ladder line connecting the collectorthereof to the base. This includes resistors 86, 87 and 88, andcapacitors 89, 90 and 91. The pulse applied through switch 51 isdifferentiated by capacitor 92 and resistor 93, with the positive pulsebeing applied through diode 94 and resistor 95 to the second mesh of thephase shift network (across capacitor The series resistor 95 acts tosoften the attack of the oscillator. The negative differentiated pulseis blocked by the diode 94. The frequency of the oscillator depends uponthe constants of the ladder line which forms the feedback circuit, andthe decay depends upon the setting of the resistor 96 which is bridgedacross capacitor 90, and which controls the Q of the feedback circuit.The thermistor 97 serves to temperature compensate the Q for temperaturechanges.

The output from the oscillator is derived from the collector oftransistor 85 and applied through resistor 98, capacitor 99, theparallel limiting diodes 100 and 101 and output leveling resistor 102 tothe output bus 103. The diodes 100 and 101 act to eliminate noise. Aseries resonant circuit including inductor 164 and capacitor 105 acts toreshape the clipped waveform from the noise elimination diodes toprovide the desired waveform.

The pedal multivibrator 70 is generally similar to the accompanimentmultivibrator 50. As shown in FIG. 1 this is operated from a keyingcircuit rather than from switch contacts operated by the pedals.Terminal iS connected to the pedal keying circuit, and a voltage thereonis applied to the differentiating circuit including capacitor 111 andresistor 112. The positive differentiated pulse is applied through diode113 to the transistor 115 of the multivibrator. This acts to cut offnormally conductive transistor 116 to produce a pulse at its collectorwhich appears on conductor 117. Transistors and 116 operate in the samemanner as transistors 79 and 80- of monostable multivibrator 50.

Switch 72 actuates the bass drum generator 74 as described inconnect-ion with FIG. l. This switch applies the pulse on conductor 117to a differentiating circuit including capacitor 119 andvresistor 120.The positive differentiated pulse is applied through diode 121 to thephase shift oscillator.

The bass drum oscillator itself includes transistor 124 having itscollector connected through a ladder line to its base. The ladder lineincludes resistors 125, 126 and 127 and capacitors 128, 129 and 130. Thefrequency of the oscillator, which is previously stated is of the orderof 66 cycles per second, is controlled by the constants of the ladderline. Variable resistor 132 controls the decay of the oscillations bycontrol of the Q of the feedback circuit. The output of transistor 124is applied from the collector thereof through level control resistor 133to the output bus 103.

The noise source for producing brush-cymbal sounds is formed by diode135, inductor 136 and capacitor 137. The `diode is back biased from the25 volt supply through resistor 138 and produces shot noise,recombination noise and l/ f noise, which is developed across theinductor 136. This noise is applied to the amplifiers includingtransistors 140 and 141, with the level being controlled by variableresistor 142 which couples signals from transistor 141 to transistor144. The amplified noise signal is applied to the emitter of transistor144 which functions as the gate of the keyer. The keyer is renderedoperative when a pulse is applied to the base electrode of transistor144 from emitter follower transistor 145. When the keyer is actuatedfrom the accompaniment manual by the connection through switch 52, thepulse from the monostable multivibrator 50 is applied through resistor150, diode 151 and resistor 152 to the coupling circuit includingcapacitor 153 and resistor 154. The positive pulse is applied acrossdiode 155 and capacitor 157, which functions as an integrating circuitto stretch the pulse. The pulse is then applied in parallel to resistor156 and the emitter follower 145. When switch contact 158 connectsresistor 159 in parallel with resistor 156, the pulse stretchercapacitor discharges more rapidly to provide a short sustain of thebrush-cymbal sound. When the switch 158 is open, `the resistance of thedischarge path is greater and a longer sustain is provided. The emitterfollower transistor 145, when conducting, applies pulses throughresistor 160 to the base of the gate transistor 144 so that the noise ispassed thereby to the series resonant circuit including capacitor 161and coil 162. The output across the coil 162 is applied through resistor163 to the output bus 103.

When switch 71 is closed so that a pulse is applied to the noise keyerfrom the pedal monostable multivibrator, the pulse is applied throughdiode 165 and resistor 152 to the coupling circuit including capacitor153 and resistor 154. This path does not include resistor 150 or asimilar resistor so that a longer duration pulse is provided to producea lon-ger brush-cymbal sound when initiated by the pedal monostablemultivibrator. This 'pulse is stretched by capacitor 157 and thenapplied to the emitter follower transistor 145. Switch 158 furthercontrols the sustain, as previously described.

The output from bus 103 is applied to an amplifier including transistorsand 171. Resistor 172 controls the feedback between the stages and isadjustable t0 provide control of the amplifier gain.

In FIG. 3 there is shown a more complex percussion system which includesthe features of the system of FIGS. 1 and 2 as previously described, andadditional features. The accompaniment multivibrator 50, which mayoperate the saine as the multivibrator 50 in the systems of FIGS. l and2, is actuated from the accompaniment keyboard through a circuit whichdiiiers somewhat from the circuit shown in FIGS. 1 and 2. The contact175 common to all of the keys is connected through resistor 176 to apositive potential which is bypassed by capacitor 177. Contacts 178 areassociated with the keys of the accompaniment keyboard below middle C,and contacts 179 are associated with the keys above middle C. When anyof the contacts 178 engages the contact 175, the potential from contactis applied -through diode 180 and resistor 181 to charge capacitor 182.Resistor 183 is provided to discharge the capacitor 182 and provide thedesired time constant. The pulse developed by the charging of capacitor182 is applied through capacitor 184 to the accompaniment multivibrator50, and the D.C. component is applied through diode 185 to a repeatercircuit 186i.

When a key above middle C is operated, one of the contacts 179 willprovide a potential from contact .175 through diode 188 and resistor 189to charge capacitor 190. Resistor 191 provides the desired timeconstant. The pulse across capacitor is applied through capacitor 192 tothe accompaniment multivibrator 50, and the D.C. component is appliedthrou-gh ydiode 193 to the repeater 186. The accompaniment multivibrator50 and the repeater 186 will, therefore, each be actuated when la keyeron the accompaniment manual is operated. After one key is operated,operation of a second key will not cause a further pulse acrosscapacitor 190 unless it is on the opposite side of the middle C break. Aswitch 195 is provided to connect the two sections so that a secondpulse cannot be produced until all keys of the manual are released and akey is then operated.

The accompaniment multivibrator 50 operates as previously described toproduce an actuating pulse for the percussion generators. Accompanimentmultivibrator 50 is connected through switch 200 to wood block generator.201, which may be the same as wood block generator 53 in FIG. l. Theaccompaniment multivibrator is connected through switch 202 to brushkeyer 203. The brush keyer selectively applies signals from the noisegenerator 204, and the noise generator and brush keyer can be identicalto the noise generator 55 and brush keyer 54 in FIG. 1. Themultivibrator 50 is also connected through switch 205 to the tom-'tomgenerator 206. The tom-tom generator may be generally similar to thewood block generator and the bass drum generator, and has a frequency ofthe order of 173 cycles per second.

The accompaniment multivibrator 50 is connected through switch 208 tothe alternator 209. The alternator may be a flip-Hop circuit, whichresponds to applied pulses to alternately apply pulses to outputconductors 210 and 211. Output conductor 210 is connected to wood blockgenerator 201 and output conductor 211 is connected to temple blockgenerator 212. The temple block generator may be of the sameconstruction as the wood block generator but has a higher frequencywhich may be of the order of 75() cycles per second. Accordingly, whenswitch 208` is closed, repeated operation of keys of the accompanimentmanual to produce repeating pulses from the accompaniment multivibrator50 will cause alternator 209 to alternately actuate the wood blockgenerator 201 and the temple block generator 212. Therefore, the tonesproduced by these generators will be alternately applied to theamplifier 214.

The repeater 186 is connected by switch 215 to snare drum generator 216and by switch 220 to clave-castinet generator 221. The repeater 186 canbe an astable multivibrator having a frequency of the order of 0 to 2()cycles per second. A variable control is provided for the repeatelnwhichcan be adjusted by the organist to the desired repetition speed.Accordingly, when a note is played on the accompaniment manual, the D.C.voltage pulse will cause the repeater to operate continuously until thepulse is terminated. It is noted that the pulses are not applied to therepeater through a capacitor so that they are not differentiated toproduce a single trigger pulse, as are the pulses applied to theaccompaniment multivibrator 50i.

The snare drum generator may be similar to the wood block `generator 53and bass drum generator 74 shown in FIG. 2, and has a frequency of theorder of 166 cycles per second. The output of the snare drum generatoris applied through an amplier 217 to aA speaker 218. The speaker 218 canbe specially designed to reproduce the sound of a snare drum.

The clave-castinet generator can be similar to the generator previouslydescribed but has a relatively high frequency of the order of 2500cycles per second. This will be operated repeatedly by the repeater 186as long as the actuating pulse is applied thereto.

The pedal multivibrator 70 is actuated by operation of the pedalsthrough switch contacts 225 connected thereto. These contacts engage thefixed contact 226 which is at ground potential. Operation of any pedalcauses actuation of relay 227 so that the sealed reed contact 228thereof engages down contact 229. This applies a positive pulse to thepedal multivibrator 70 to actuate the same each time a pedal isoperated. When the pedal is released, the reed contact 228 returns intoengagement with the upper contact 230. This applies a pulse to the pedalup multivibrator 231 to actuate the same.

The pedal down multivibrator 7 0 is connected through switch 232 to thebase drum generator 233. Bass drum generator 233 `can be identical tothe bass drum generator 74 shown in FIG. 2, and is actuated by themultivibrator 70 in exactly the same manner. The pedal multi-vibrator 70is connected through switch 235 to the brush-cymbal keyer 236. Thebrush-cymbal keyer is connected to the noise generator 204 and operatesin the manner previously described in connection with FIG. 2. The pedalmultivibrator 70 is -connected through switch 238 to the temple blockgenerator 212, and through switch 241i to the tonitom generator 206,which have previously been described. Accordingly, actuation of thepedal multivibrator causes operation of the bass drum generator, thebrush-cymbal keyer, the temple block generator and the tom-tomgenerator, when the switches 232, 235, 238 and 240 are closed. Theswitches are provided as stops for the organist to control so that anyone or m-ore can be operated at any time.

The pedal up multivibrator 231 is connected through switch 241 to thebrush-cymbal keyer 206. Accordingly, the brush-cymbal keyer can beoperated when a pedal has been operated and is released. When bothswitches 235 and 241 are both closed, the keyer 236 will be operatedwhen a pedal is operated and again when it is released. Operation ofeither of these switches `will cause the keyer to operate at one or theother of the times.

The brush-cymbal keyer is also connected to switch 242 which selectivelygrounds a terminal of the brush-cymbal keyer to provide short sustain ofthe burst of noise signal provided by the keyer. This switch isequivalent to the switch 158 in FIG. 2 which controls the sustain of thekeyer 54. In the system of FIG. 3, a separate keyer is provided for theaccompaniment brush sound and for the pedal brush-cymbal sound. Thismakes it unnecessary to change the operation of the keyer when actuatedby the accompaniment and pedal multivibrators. The brush-cymbal keyer236 is also controlled by shimmer generator 244. This is a generatorwhich provides a frequency of the order of 14 cycles per second, whichmodulates the amplitude of the noise signals passed by the keyer, toprovide a shimmer effect.

The outputs of the wood block generator 201, the brush keyer 203, thetom-tom generator 206, the temple block generator 212 and thebrush-cymbal keyer 236 are all fed to amplifier 214. The output ofamplifier 214 is applied to the string channel post amplifier 245 and tothe string power amplifier 246. The output of the string channel postamplifier 245 is also applied to the power amplifier 246. This isgenerally the same connection shown in FIG. 1, but in that system all ofthe percussion sounds are applied to the string channel. The `stringpower amplifier 245 dri-ves one or more loudspeakers indicated as 247and 248. The output of the `clave-castinet amplifier 221 and o-f thebass drum generator 233 are applied to amplifier 250. Amplifiers 214 and250 may have a common gain control, as indicated by the arrow 249. Theoutput of amplifier 250 is applied to the fiute channel of the organ,being applied to the flute channel post amplifier 251 and to the -poweramplifier 252. The flute channel post amplifier 251 output is alsoapplied to the power amplifier 252. This permits control of the outputboth by the amplifier 250 and by the flute channel post amplifier 251.The output of the power amplifier 252 is applied to loudspeakers 254 and255. One of these speakers may be a speaker including a rotating memberto provide a tremolo effect, as is commonly used in the finte channel ofau organ.

The percussion system which has been described maybe provided in variousdifferent forms, as illustrated by the simple form shown in FIG. 1, andthe more complex form shown in FIG. 3. In each case, generatorsproviding the sounds of percussive instruments are selectively actuatedby multivibrators controlled by the accompaniment manual and the pedalboard of an organ. Various difierent generators for simulating variousinstruments can be provided as may be desired in a particularapplication. The accompaniment manual can control the generators througha repeater to provide the repeated -sounds of a snare drum andclave-castinet. An alternator can be used to give alternate sounds ofdifferent types, such as alternate Wood block and temple block sounds.The generators when controlled by the pedals can operate when a pedal isdepressed and/ or when a pedal is released. This provides a widelatitude in arrangements which can be made.

I claim:

1. A percussion system for an electronic organ having keys `forproducing notes of a musical scale and sound reproducing means, saidsystem including in combination, trigger means for providing a triggerpulse in response to operation of a key, alternator means having firstand second terminals and responsive to successive trigger pulses toalternatively provide actuating pulses at said first and secondterminals, first and second generators coupled to the sound reproducingmeans for applying thereto signals of different frequencies, each ofsaid tone generators being responsive to the application of an actuatingpulse thereto to produce a signal pulse, and means connecting said firstand second terminals to said first and second generators respectively sothat signals are alternatively applied therefrom to the soundreproducing means by operation of the organ keys.

2. A percussion system for an electronic organ having keys on a manualfor producing notes of a musical scale which extend above and below areference note, and sound reproducing means, said system including incombination, trigger means lfor providing an actuating pulse, -meanscoupled to said trigger means and responsive to operation of the keys toactuate said trigger means, with operation of a key for a note below thereference note causing actuation of said trigger means and operation ofa key for a note above the reference note causing a further actuation ofsaid trigger means, a plurality of generator means coupled to the soundreproducing means for applying thereto signals of different`frequencies, each of said generator means being responsive to theapplication of an actuating pulse thereto to produce a signal pulse, andswitching means selectively connecting said trigger means to saidgenerators so that signal pulses are selectively applied to the soundreproducing means by operation of the keys.

3. A percussion system for an electronic organ having keys on a manualfor producing notes of a musical scale which extend above and below areference note, tand sound reproducing means, said system including incombination, trigger means for providing an actuating pulse, actuatingmeans coupled to said trigger means and responsive to operation of thekeys to Iactuate said trigger means by operation of a key for a notebelow the reference note and again by operation of a key for a noteabove the reference note, a plurality of generator means coupled to thesound reproducing means for applying thereto signals of differentfrequencies, each of said generator means being responsive to theapplication of an actuating pulse thereto to produce a signal pulse, anoise generator, keyer means coupled to said noise generator forselectively applying noise signals therefrom to the sound reproducingImeans, and switching means selectively connecting said trigger means tosaid generator means and to said keyer means, so that signal pulses areselectively applied to the sound reproducing means by operation of thekeys.

4. A percussion system for an electronic organ having keys provided byat least one manual and a pedal board, and sound reproducing means, saidsystem including in combination, iirst trigger means for providing anactuating pulse in response to operation of a key of the manual, secondtrigger means for providing an -actuating pulse in response to operationof a pedal key, third trigger means for providing an actuating pulse inresponse to release of an actuated pedal key, a plurality of generatorscoupled to the sound reproducing means for applying thereto signals ofdifferent frequencies, each of said generators being responsive to theapplication of an actuating pulse thereto to produce a signal pulse, andswitching means selectively connecting said first, second and thirdtrigger means to said generators so that signal pulses are selectivelyapplied to the sound reproducing means by operation of the keys of themanual and pedal board.

5. A percussion system for an electronic organ having keys provided byat least one manual and a pedal board, and sound reproducing means, saidsystem including in combination, first trigger means for providing anactuating pulse in response to operation of a key of the manual, saidrst trigger means including means providing repeated actuating pulses,second trigger means for providing an actuating pulse in response tooperation of a pedal key and in response to release of an operated key,a plurality of generators coupled to the sound reproducing means Iforapplying thereto signals of different frequencies, each of said tonegenerators being responsive to the application of an actuating pulsethereto to produce a signal pulse, generator means producing 10 randomnoise signals, keyer means coupled to said generator means forselectively applying said random noise signals to the sound reproducingmeans, said keyer means being responsive to the application of anactuating pulse to provide a burst of random noise signals havingpredetermined attack and decay characteristics, alternator meansconnected to a pair of said tone generators for applying actuatingpulses thereto in turn in response to successive actuating pulsesapplied to said alternator means, and switching means selectivelyconnecting said rst and second trigger means to said generators, saidkeyer means and said alternator means, so that signals are selectivelyapplied to the sound reproducing means by operation of the keys of themanual and pedal board.

References Cited UNITED STATES PATENTS 3,309,454 3/1967 Cutler et al84--1.l7 3,327,047 6/ 1967 Slaats 84--1.24 3,358,069 12/ 1967 Hearne84-1.03

JOHN S. HEYMAN, Primary Examiner.

B. P. DAVIS, Assistant Examiner.

U.S. Cl. X.R. 84-1.03, 1.24

